Search

Zika virus (ZIKV) is a vector-borne flavivirus that has caused recent outbreaks associated with serious disease in infants and newborns in the Americas. Aedes mosquitoes are the primary vectors for ZIKV, but little is known about the diversity of mosquitoes that can transmit ZIKV in North America. We chose three abundant North American mosquito species ( Anopheles freeborni , Anopheles quadrimaculatus , and Culex tarsalis ) and one known vector species ( Aedes aegypti ), fed them blood meals supplemented with a recent outbreak ZIKV strain, and tested bodies, legs, and saliva for infectious ZIKV. ZIKV was able to infect, disseminate, and be transmitted by Aedes aegypti . However, Anopheles freeborni , Anopheles quadrimaculatus , and Culex tarsalis were unable to be infected. We conclude that these species are unlikely to be involved in ZIKV transmission in North America. However, we should continue to examine the ability for other mosquito species to potentially act as ZIKV vectors in North America., Competing Interests: The authors declare there are no competing interests.

Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae , Anopheles stephensi , and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae , Anopheles stephensi , and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae , Anopheles stephensi , and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus., Competing Interests: The authors declare there are no competing interests.

Anopheles gambiae densovirus (AgDNV) is a potential microbial agent for paratransgenesis and gene transduction in An. gambiae , the major vector of human malaria in sub-Saharan Africa. Understanding the interaction between AgDNV and An. gambiae is critical for using AgDNV in a basic and applied manner for Anopheles gene manipulation. Here, we tested the effects of mosquito age, sex, blood feeding status, and potential for horizontal transmission using an enhanced green fluorescent protein (EGFP) reporter AgDNV system. Neither mosquito age at infection nor feeding regime affected viral titers. Female mosquitoes were more permissive to viral infection than males. Despite low viral titers, infected males were able to venereally transmit virus to females during mating, where the virus was localized with the transferred sperm in the spermathecae. These findings will be useful for designing AgDNV-based strategies to manipulate Anopheles gambiae ., Competing Interests: The authors declare that they have no competing interests.

The blacklegged tick Ixodes scapularis is widely distributed in the United States and transmits multiple pathogens to humans, wildlife and domestic animals. Recently, several novel viruses in the family Bunyaviridae (South Bay virus (SBV) and Blacklegged tick phlebovirus (BTPV)) were identified infecting female I. scapularis ticks collected in New York State. We used metagenomic sequencing to investigate the distribution of viruses infecting male and female I. scapularis ticks collected in Centre County, Pennsylvania. We identified both SBV and BTPV in both male and female ticks from all collection locations. The role of male I. scapularis in pathogen epidemiology has been overlooked because they rarely bite and are not considered important pathogen vectors. However, males may act as reservoirs for pathogens that can then be transmitted to females during mating. Our data highlight the importance of examining all potential avenues of pathogen maintenance and transmission throughout the vector-pathogen life cycle in order to understand the epidemiology of tick-borne pathogens.

Mosquito densoviruses (DNVs) are candidate agents for paratransgenic control of malaria and other vector-borne diseases. Unlike other mosquito DNVs, the Anopheles gambiae DNV (AgDNV) is non-pathogenic to larval mosquitoes. However, the cost of infection upon adults and the molecular mechanisms underpinning infection in the mosquito host are unknown. Using life table analysis, we show that AgDNV infection has minimal effects on An. gambiae survival (no significant effect in 2 replicates and a slight 2 day survival decrease in the third replicate). Using microarrays, we show that AgDNV has very minimal effect on the adult mosquito transcriptome, with only 4-15 genes differentially regulated depending on the statistical criteria imposed. The minimal impact upon global transcription provides some mechanistic understanding of lack of virus pathogenicity, suggesting a long co-evolutionary history that has shifted towards avirulence. From an applied standpoint, lack of strong induced fitness costs makes AgDNV an attractive agent for paratransgenic malaria control.